How does one prevent plants growing in cracks of buildings?

Question

There are "peepal" seedlings (Ficus religiosa) seedlings growing in cracks of a residential apartment about 30 years old in Mumbai, India, resulting in seepage of rain water during monsoons. Any suggestions to prevent this would be deeply appreciated. My assumption is that these seedlings grow out of seeds carried by bird droppings.

Answer 1

Your assumption is very likely right, the seeds may also be wind borne.

In order for a seed to germinate and take root it needs moisture and some small amount of soil material.  Cracks offer seeds several advantages,,, they trap moisture, they trap soil or debris, and they provide an irregular surface for the roots to cling to.  Here in the southern US we get ferns and grasses doing the same thing.  Once the plant roots start growing the turgid pressure from the root will expand the existing crack making it even larger or deeper.

Only solution I know of is to fill the cracks after cleaning them.

Starting at the TOP of the building and working your way down, clean the cracks by scrapping the debris out or power washing it out.  Then starting at the TOP again, use a suitable joint or crack filling material and fill all of the cracks flush with the surrounding material.

Starting at the top prevents, or lessens, the chance of material being trapped behind the work you are doing as a repair.

The use of a herbicide ( weed killer ) is not going to work well except in the short term as it will kill only the growing plants but not address any existing or future seeds nor does this really address the reason the plants are growing there in the first place.

Answer 2

Can you buy weed killer there?

Answer 3

Use a total vegetation killer if it is available to you. Trade name of one is ortho ground clear. Clean any debris from the affected areas first.  

Answer 4

Treat with weed killer then fill in the cracks